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AndyL

Adjusting the OPV (over Pressure Valve) Gaggia Classic

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I´ve lowered the pressure to around 10 bar (shown on the gauge). My measurements are 16g in/ around 60-65 g out, 62°C, pure Arabica.

What do you mean with "back off grind"? Finer or coarser?

 

Greets

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How do you drink it/ with/ without milk , your ratio sounds like a very long black.

Usual starting ratio is 1 to 2. i.e. 18 gms coffee / 36 gms brew in about 25 / 28 secs brew temp /. 92 - 94.

By back off I meant grind very slightly coarser. Before you do try using the same settings but allow 25 - 30 sec and measure your brew.

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Sorry if this is on the forums somewhere, but I can't find it.

 

Can anyone tell me what kit I need to purchase to make a pressure gauge? I've got a spare standard PF handle. I juts need to know what thread I need on the pressure gauge to fit the handle thread and anything else I need to get besides thread tape.

 

Cheers

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Sorry if this is on the forums somewhere, but I can't find it.

 

Can anyone tell me what kit I need to purchase to make a pressure gauge? I've got a spare standard PF handle. I juts need to know what thread I need on the pressure gauge to fit the handle thread and anything else I need to get besides thread tape.

 

Cheers

 

https://coffeeforums.co.uk/showthread.php?6174-Gaggia-Classic-Portafilter-Pressure-Gauge-OPV-mod

 

there you go - sometimes its easier to find on google - but most good info leads back to the forum :D


keep calm and grind flat

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Sorry if this is on the forums somewhere, but I can't find it.

 

Can anyone tell me what kit I need to purchase to make a pressure gauge? I've got a spare standard PF handle. I juts need to know what thread I need on the pressure gauge to fit the handle thread and anything else I need to get besides thread tape.

 

Cheers

There's one on ebay that might work out cheaper than buying the bits separately.

Laissez les bons temps rouler

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After lots of experiments I found out that 9,5bar static works best for me. I don't think slow extraction flow gives us 1 bar difference, more likely 0,5 bar.

BR


GaggiaEnthusiast

 

Buying expensive equipment won't make you barista!

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After lots of experiments I found out that 9,5bar static works best for me. I don't think slow extraction flow gives us 1 bar difference, more likely 0,5 bar.

BR

 

I just adjusted the OPV on a second Classic I just got as a spare. Right now it's 9.5 static so I'll try that out and see. My current Classic measured 10.3 today, so it seems I've been using a touch too much pressure.

 

Update: reduced my current Classic to 9.7. We'll see the results. Don't know how evident they will be.

Edited by les24preludes

Gaggia Baby 2002 and 2005, Mazzer Major, Motta 58.4mm tamper

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Hi guys, I only got about 180 degrees till it felt like I could turn no further, any thoughts?

 

Bit more background. Initial pressure test was off the scale, so I turned off immediately and proceeded to turn the 5mm. It was tight to get moving, but the machine was cold and ten years old so to be expected (gap to get my sockets back)

 

If I turn clockwise it’s fine, then anti-clockwise and it hits the buffer again so guess I’m quite out of sync!)

 

Before I turn the machine on again, thought I’d come back to the forum for thoughts. Because the ‘anti-clockwise’ comment and my experience feels count-intuitive. Feels like I’m now on max pressure, when it should be loosened to reduce pressure.

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Hi guys, I only got about 180 degrees till it felt like I could turn no further, any thoughts?

 

Bit more background. Initial pressure test was off the scale, so I turned off immediately and proceeded to turn the 5mm. It was tight to get moving, but the machine was cold and ten years old so to be expected (gap to get my sockets back)

 

If I turn clockwise it’s fine, then anti-clockwise and it hits the buffer again so guess I’m quite out of sync!)

 

Before I turn the machine on again, thought I’d come back to the forum for thoughts. Because the ‘anti-clockwise’ comment and my experience feels count-intuitive. Feels like I’m now on max pressure, when it should be loosened to reduce pressure.

It's definately anti-clockwise to reduce pressure. It can be a bit of a mare to loosen of initially especially if it hasn't been done before. I used an allen bit in a screwdriver with another one through the handle for leverage when I did mine.

Laissez les bons temps rouler

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It’s really odd, I turned it clockwise and it dropped to 12 bar. It’s very stuttery too so I’m wondering whether the gauge has had it.

 

I still suspect I’ve got a blocked thread too as I’ve only got 360 to 450 degree of total adjustment from top to bottom

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Hey, I attempted this mod today, I was able to get the portafilter rigged up with a pressure gauge and adjust the OPV without much issue. However, no matter what I do the pressure needle just stays maxed out around 14 bar when the machine is on. If I open the steam valve, the pressure drops as you would expect. I have done 3 full turns anticlockwise and had apparently no change in pressure. Has anyone experienced anything like this? I decided not to keep adjusting the OPV after 3 rotations, but I didn't experience any resistance so presumably it could go further? Not sure if there are any risks to that so I backed off for now and put things as they were.

 

It's possible that my pressure gauge assembly has an issue but I'm not sure how much could go wrong with that, and I would expect any leaks or issues to result in lower reported pressure.. furthermore the pressure does drop as expected when tweaking the steam valve.

 

This machine is secondhand and around 13 years old, not sure if anyone else attempted mods or replaced parts before me so it may not have been at stock settings. Is it safe to just keep turning anticlockwise and see if the pressure eventually drops? Or could it be that the OPV is simply broken?

 

Thanks.

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chances are that with a 13 yr old machine the opv has been replaced or fiddled with - keep adjusting should be ok


keep calm and grind flat

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Does the earth wire need to be removed from the top of the machine to do this or is it just to make things a bit easier? I'd rather not touch it and just leave it where it is...

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Does the earth wire need to be removed from the top of the machine to do this or is it just to make things a bit easier? I'd rather not touch it and just leave it where it is...

leave it as it is, and work on OPV


GaggiaEnthusiast

 

Buying expensive equipment won't make you barista!

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It’s just easier to work on the machine without the top earth wire connected so you can remove the whole top/funnel assembly.

 

if you can work on the machine with it connected then do so. Otherwise it does simply pull off. Make sure you pull on the connector, not the cable as you don’t want the cable pulling off the crimp connector.

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Done the OPV mod today and just left the earth wire connected. Can't believe how much better my espresso is tasting - wish I done this years ago!

 

Took me a couple of hours to do everything. Getting the spout off the portafilter was a right headache and then the tube wouldn't come off the opv. Worth the effort though :good:

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Done the OPV mod today and just left the earth wire connected. Can't believe how much better my espresso is tasting - wish I done this years ago!

 

Took me a couple of hours to do everything. Getting the spout off the portafilter was a right headache and then the tube wouldn't come off the opv. Worth the effort though :good:

 

It does make a difference doing the OPV. Have you tried switching to something live Volvic (I couldn’t believe how much changing the water makes a difference).


Sage DB; Mazzer Major; VST 15g, 18g & 20g Baskets;TORR Trapez & Perger Tamper

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Just done my own OPV, taste is a little changed, big difference is with the cream and process. Before I was having to tamp down really quite hard to stop the water spurting through, now even a gentle tamp allows the water to pass through more slowly.

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Posted (edited)

Just did this, reading 10 bar on the pressure gauge now! Took a few adjustments as the first 270 only brought it down from 13.5 to 12bar.

I used a 2 adjustable spanner technique (one more or less vertical and one perpendicular clamped on the handle of the vertical one) as i don't have anything big enough to remove the OPV valve.

Even though OP wrote this 8 years ago it is all fantastic.

Edited by Egglet

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Great post! With the right tools this was very simple to do. Using the ratchet socket wrench with an extension made it super easy.

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Thanks for this post - followed it yesterday and got it all sorted in no time and managed to get bang on 10 bar on the second attempt! Having all the right tools made it simple but the trickiest bit for me was getting the spout off the portafilter - having a workbench vice really helped here.

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